1. Field of the Invention
This invention relates to transient suppressors for radar seekers in homing missiles.
2. Description of Related Art
With a radar-guided missile, the seeker output is generally not very smooth. During mid-course, the target signal strength may be low and the receiver output is then rather noisy. Near intercept, the signal is strong, but there may still be substantial irregular spikes on the output due to glint effects, i.e. sudden changes of the point of reflection of the radar signal.
With the seeker output being used to steer the missile, these disturbances cause corresponding disturbances to the missile body motion and to the trajectory itself. During mid-course, the transient noise can seriously disturb the trajectory and can cause a significant amount of induced drag on the missile (and perhaps also use up hydraulic fluid because of fluctuating fin deflection). Nearer intercept, the glint `spikes` may well increase the miss distance.
It is known to incorporate a "mid-course filter" in the system, to smooth out the noise due to low target signal strength. The lag associated with this filter has a slugging effect on the overall system response to guidance signals, but this does not matter until the missile is fairly close to the target, i.e. during the terminal phase. Then, the filter is generally removed, or the lag is drastically reduced.
In the terminal phase, the glint spikes may be clipped by incorporating some limiting in the signal processing.